Question

A convex lens of focal length 10cm at what distance from the lense shoud be the object be placed so that it forms a real and inverted image of 20cm away from the lense what shoud be the size of image formed if the size of the object is 2cm hight

Answer 1

Answer:

The answer is given below

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Explanation:

focal lenght = f = 10 cm

                    v = 20 cm

  we know

                  1/v + 1/u = 1/f

                  1/20 + 1/u = 1/10

                  1/20 = 1/10 - 1/u

                  1/u = 1/20 - 1/10                                           LCM= 2 x 2 x 5

                  1/u = 1-2/20                                                         = 20

                  1/u = -1/20

                   u = -20 cm

   h = height of the image

   h1 = height of the object

    h/h1 = -v/u

    h/2 = -20/20

     h = 2

     

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